<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>

</head>
<body>

<div id="div1" >
    <div>{{sumTotal}}</div>
</div>
<script>


    const vueObj = new Vue({
        el: '#div1',
        data: {
            number1: "100",
            number2: "200",

        },
        computed:{
            sumTotal: function () {
                return parseInt(this.number1) + parseInt(this.number2);
            },
        }

    });
</script>
</body>
</html>